Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain ATR-GIE Avions de Transport Régional Model ATR42-300, -320, -500, ATR72-201, and -212A airplanes and all ATR-GIE Avions de Transport Régional Model ATR72-102, -202, -211, and -212 airplanes. The NPRM was published in the Federal Register on August 21, 2025 (90 FR 40778). The NPRM was prompted by AD 2025-0080, dated April 11, 2025; corrected April 23, 2025 (EASA AD 2025-0080) (also referred to as the MCAI), issued by EASA, which is the Technical Agent for the Member States of the European Union. The MCAI superseded EASA AD 2025-0024, dated January 22, 2025. The MCAI states that during an inspection on the ATR final assembly line, a fire extinguishing tube, located on the ceiling of the aft cargo compartment, was found disconnected from its sleeve. Further investigations indicated that this condition might affect other ATR airplanes. This condition, if not detected and corrected, could affect the capability of the aft cargo compartment fire extinguishing system to contain a cargo compartment fire. In the NPRM, the FAA proposed to require a functional check of the aft cargo fire extinguishing system and applicable on-condition actions, if necessary, as specified in EASA AD 2025-0080. The FAA also proposed to require, for certain airplanes, an additional functional check and applicable on-condition actions, as specified in EASA AD 2025-0080. The FAA is issuing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-2262. Discussion of Final Airworthiness Directive Comments The FAA received comments from the Air Line Pilots Association, International (ALPA) and an individual who supported the NPRM without change. Conclusion These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed EASA AD 2025-0080, which specifies procedures for accomplishing a functional check for discrepancies, such as incorrectly installed distribution piping, of the aft cargo fire extinguishing system, and depending on the results, corrective actions. Corrective actions include correcting and re-installing the distribution piping then repeating the functional check after re-installation, or obtaining and following repair instructions from the manufacturer if a detected discrepancy cannot be corrected. For airplanes on which a functional check and corrective actions have been accomplished using certain material, EASA AD 2025-0080 specifies performing an additional functional check and, depending on the results, corrective actions. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. Costs of Compliance The FAA estimates that this AD affects 103 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Costs for Required Actions Labor cost Parts cost Cost per product Cost on U.S. operators 1 work-hour × $85 per hour = $85 $0 $85 $8,755 The FAA estimates the following costs to do any necessary on-condition actions that would be required based on the results of any required actions. The FAA has no way of determining the number of aircraft that might need these on-condition actions: Estimated Costs of On-Condition Actions Labor cost Parts cost Cost per product Up to 2 work-hour × $85 per hour = $170 $0 Up to $170. The FAA has received no definitive data on which to base the cost estimates for airplanes that require contacting ATR for repair instructions in order to comply with on-condition actions specified in this AD. Authority for This Rulemaking Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. Regulatory Findings This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. For the reasons discussed above, I certify that this AD: (1) Is not a "significant regulatory action" under Executive Order 12866, (2) Will not affect intrastate aviation in Alaska, and (3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39-AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2025-23-04 ATR-GIE Avions de Transport Régional: Amendment 39-23187; Docket No. FAA-2025-2262; Project Identifier MCAI-2025-00083-T. (a) Effective Date This airworthiness directive (AD) is effective January 13, 2026. (b) Affected ADs None. (c) Applicability This AD applies to the ATR-GIE Avions de Transport Régional airplanes identified in paragraphs (c)(1) and (2) of this AD, certificated in any category, as identified in European Union Aviation Safety Agency (EASA) AD 2025-0080, dated April 11, 2025; corrected April 23, 2025 (EASA AD 2025-0080). (1) ATR42-300, -320, and -500 airplanes. (2) ATR72-102, -201, -202, -211, -212, and -212A airplanes. (d) Subject Air Transport Association (ATA) of America Code 26, Fire Protection. (e) Unsafe Condition This AD was prompted by an inspection on the ATR final assembly line that found a fire extinguishing tube, located on the ceiling of the aft cargo compartment, disconnected from its sleeve. The FAA is issuing this AD to address this condition, which if not detected and corrected, could affect the capability of the aft cargo compartment fire extinguishing system to contain a cargo compartment fire. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Requirements Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, EASA AD 2025-0080. (h) Exceptions to EASA AD 2025-0080 (1) Where EASA AD 2025-0080 refers to its effective date, this AD requires using the effective date of this AD. (2) Where EASA AD 2025-0080 refers to February 5, 2025 (the effective date of EASA AD 2025-0024, dated January 22, 2025), this AD requires using the effective date of this AD. (3) Where EASA AD 2025-0080 refers to "any discrepancy", this AD requires replacing that text with "any incorrectly installed distribution piping". (4) This AD does not adopt the "Remarks" section of EASA AD 2025-0080. (i) Special Flight Permits Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the airplane to a location where the airplane can be modified, provided no cargo is in the aft cargo compartment. (j) Additional AD Provisions The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible Flight Standards Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (k) of this AD and email to: AMOC@faa.gov . Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or EASA; or ATR-GIE Avions de Transport Régional's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. (k) Additional Information For more information about this AD, contact Alexis Whitaker, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7309; email: 9-AVS-AIR-BACO-COS@faa.gov. (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this material as applicable to do the actions required by this AD, unless this AD specifies otherwise. (i) European Union Aviation Safety Agency (EASA) AD 2025-0080, dated April 11, 2025; corrected April 23, 2025. (ii) [Reserved] (3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. (5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov. Issued on November 7, 2025. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.